The correct option is
D For
Option A- By is used to indicate means, nearness, time, order, according to, manner or instrument, measure, in the name of. Since this preposition does not fit correctly in the given sentence, it is incorrect.
Option B- From is used to indicate movement, since, source, cause, separation, distance and protection. Thus it is incorrect.
Option C- Off is used to indicate separation and disconnection. This does not fit correctly in the given sentence. Hence it is incorrect.
Option D- For is used to indicate purpose, cause, direction, a period of time, on behalf of, with regard to. In the given sentence A certain cause is indicated. Hence 'for' is the correct answer.